Typically, electricity provided to energy consuming devices is fungible, e.g., different components of the electricity are indistinguishable from the perspective of the device. For example, electricity can be provided by a variety of sources, such as renewable and non-renewable sources, but one cannot readily connect to an electrical grid and distinguish between renewable and non-renewable power on the grid. Since renewable and non-renewable energy are fungible, consumers have traditionally been indifferent to how electrical energy is sourced. However, as environmental considerations have come to the forefront of energy policy, the demand for “green” or renewable energy has increased substantially. Current mechanisms for distinguishing green energy from “brown” or fossil fuel energy are typically simple accounting mechanisms, e.g., an entity might buy a given amount of renewable electrical energy to meet regulatory requirements, obtain a tax credit, etc. However, the actual electrical energy that entity draws from the grid is typically still provided by both renewable and non-renewable sources.
Another problem faced by electrical grid operators is that there is very little direct control over electrical consumers. Typically, a given electrical device can simply plug into an outlet and begin drawing power, and the grid operator has very limited mechanisms for requesting that devices stop drawing power if need be, e.g., because the grid is undersupplied. Ideally, the grid operator would have more refined mechanisms for allocating power consumption to individual power consumers.